Rotary pumps



Feb. 20, 1968 F. w. MCCOMBIE ROTARY PUMPS 6 Sheets-Sheet 1 Filed Oct. 12, 1965 INVENTOR 2% 104m! 7mg flTTORNEY Feb. 20, 1968 F. w. m c omsla ROTARY PUMPS 6 Sheets- Sheet 2 Filed Oct. 12, 1965 ATTORNEY Feb. 20, 1968 F. w. M COMBIE 3,369,495

ROTARY PUMPS Filed Oct. 12, 1965 6 Sheets-$heet 5 73 gg I9 is 23 Fig.5.

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ATTORNfY lNvLwrok M mam-A MM Feb. 20, 1968 F.'W. MCCOMBIE 3 9 ROTARY PUMPS Filed Oct. 12, 1965 6 Sheets-$heet 4 flTTO/EWEY 3,369,495 Patented Feb. 20, 1968 3,369,495 ROTARY PUMPS Frederick W. McCombie, London, England, assignor to Megator Pumps and Compressors Limited, London, England, a British company Filed Oct. 12, 1965, Ser. No. 495,173 Claims priority, application Great Britain, Mar. 5, 1965, 9,521/ 65 1 (Ilairn. (Cl. 103163) ABSTRACT OF THE DISCLOSURE This invention relates to rotary pumps of the kind including a casing having suction inlet and discharge outlet openings and having a fiat front face for the reception of a cover having ports and passages for controlling the flow of pumped liquid from the point where it enters the pump casing via the suction inlet opening to the point where it leaves the pump casing via the discharge outlet opening, spaced bearings in the casing carrying a horizontally arranged rotatable shaft carrying one or more eccentrics, each revolvable in a shoe which in conjunction with the eccentric forms a displacement chamber, a port plate formed with suction and delivery ports and fixed to or associated with the cover so that the port plate lies between the cover and the shoe or shoes, the latter being reciprocable over the surface of the port plate by the action of the eccentric r eccentrics and maintained in sealing engagement therewith by the pressure of liquid in the casing, the suction and delivery ports in the port plates being opened and closed by the shoe or shoes as a result of their reciprocatory movement over the port plate to admit liquid to the displacement chamber or chambers and permit delivery of the liquid displaced therefrom.

In pumps constructed in accordance with our earliest U.S. Patent No. 2,561,808, there was a tendency for stagnation or the settlement of solid matter to occur in the casing. This was to a large extent overcome by a construction including a deflector or baflie or alternatively an externally arranged pipe and forming the subject of our U.S. Patent 2,612,846.

In pumps constructed in accordance with U.S. Patents 2,561,808 and 2,612,846, the pumped liquid passed through the pump casing in contact with the working parts, which were therefore subject to wear if the liquid contained much grit or other solid matter. This was overcome by an alternative construction whereby the pumped liquid passed to the discharge outlet without passing through the casing in contact with the working parts and a service of clean liquid under pressure was applied to the casing. This alternative construction, which forms the subject of our U.S. Patent 2,561,810 required the design and production, for dealing with dirtier liquids, of a pump materially different from the regular pump produced for the cleaner liquids.

The principal objects of the present invention are, first, to evolve a mode of construction by which pumps designed for a service of clean liquid to the casing need only differ as regards a single part, namely, the cover, from the regular pumps produced without this feature, an economy in cost of manufacture and carrying of stocks being thereby effected, secondly, to improve further the flushingof the casing for prevention of stagnation or the settlement of solids, and thirdly, to simplify the means of etfecting this flushing by eliminating the deflector or external pipe described in our U.S. Patent 2,612,846.

A rotary pump of the kind set forth and in accordance with the present invention includes a casing having two or more ports passing from the interior through the lower part of the machined facing to which the cover is fastened. In the case of pumps not having a service of clean liquid, these ports register with ports leading to passages within the cover. The pumped liquid, after issuing from the shoes, passes through a passage in the cover, enters the casing through one of these ports, circulates round the lower portion of the casing and passes out of the casing through another of the ports into another passage in the cover and thence to the discharge outlet of the pump. In the case of pumps having a service of clean liquid to the casing, the same body is used, but with an alternative cover which contains the necessary passages to convey the pumped liquid from the inlet passage in the casing to the shoes and from the shoes to the outlet passage in the casing without passing through the main part of the casing containing the working parts. The fact that the same body is used for either type of pump and that only the cover differs, ettects a great economy in production and in stocking.

With the improved construction in accordance with the present invention, in the case of regular pumps not having a service of clean liquid, the discharge from all the shoes enters the lower part of the casing in a uniform stream, and since it passes out of the casing through a port alongside the port of entry, a vortex or continuous circulatory flow is maintained in the lower part of the casing, resulting in improved scavenging of solid matter and reduced possibility of stagnation.

In the case again of pumps not having a service of clean liquid, it will be seen that a single passage cast in the cover supersedes the deflector or external pipe shown in our U.S. Patent 2,612,846, a simpler and cheaper con'- struction being thereby provided.

Referring to the accompanying drawings:

FIGURES 1 and 2 illustrate a pump in accordance with the invention fitted with alternative covers for use where a service of clean liquid is not available or is available respectively;

FIGURE 3 is a view of the cover fitted to the pump as in FIGURE 1 and looking on the inside face of the cover;

FIGURE 4 is a section through the cover viewed from the outer side of the cover showing the formation of the passages therein;

FIGURE 5 is a section on the line AB in FIG- URE 4;

FIGURE 6 is a section on the line CD in FIG- URE 4;

FIGURE 7 is a section on the line E-F in FIG- URE 4;

FIGURE 8 is a similar view to FIGURE 3 but illustrating the cover fitted as in FIGURE 2;

FIGURE 9 is a section taken on the same line as FIGURE 4 but illustrating the cover in FIGURE 8;

FIGURE 10 is a section on the line G-H in FIGURE 9;

FIGURE 11 is a section on the line J-K in FIGURE 9; and

FIGURE 12 is a section on the line L-M in FIGURE 9.

It will be appreciated that usually a service of clean liquid will not be available and in this case the pump casing will be fitted with a cover as in FIGURE 1, the liquid in this case circulating through the bottom of the casing to prevent an accumulation of grit and other impurities at the bottom of the casing. This particular cover has been designed with this object in view and to cause a vortex in the liquid suflicient to ensure grit or the like being swept out of the casing and out of the pumps discharge outlet.

If a clean service of liquid is however available this cleansing of the pump casing is no longer necessary and it is possible for the liquid to take a more direct path 3 through the pump, thereby improving its efliciency. Consequently the cover fitted to the pump as in FIGURE 2 has been specially designed for use where a clean service of liquid is available.

The type of cover normally fitted will first be described.

The pump includes a casing 1 having a suction inlet 2 and discharge outlet 3 at its upper end, the casing being fitted with bearings for a shaft 4 driven in any suitable manner and carrying one or more eccentrics 5, each revolvable in an associated displacement chamber or shoe 6 which is reciprocable vertically over a port plate 7, the port plate being provided with ports 8 and 8a which co operate with ports in the shoe which under the reciprocating action of the shoe control the flow of liquid to and from the interior of the shoe, the shoe in, conjunction with the eccentric forming a variable displacement chamber to draw liquid through the suction inlet 2 and discharge the liquid through the discharge outlet 3 in known manner.

The front open face of the casing is closed by a cover 9 as in FIGURE 1 or the alternative type of cover 10 illustrated in FIGURE 2.

Dealing in the first case with the cover 9 the cover is hollow and incorporates a number of liquid passages hereinafter described with which the liquid contained in the pump casing and displacement chambers has access through suitably arranged ports.

The flat front face the pump casing to whichthe cover is secured is formed with two ports which register with correspondingly shaped ports 11 in the cover which are connected with the suction inlet 2 by an internal pocket 12 so that all the liquid entering the inlet 2 has to pass through the ports 11 on its way to the displacement chambers.

The casing is formed with a third port whichregisters with a port 13 in the cover likewise connected by a pocket 14 with the discharge outlet 3.

The casing is furthermore provided at its lower end with a port which registers with a port 15 in the cover for the entry of liquid into the lower part of the casing and a port which registers with a port 16 in the cover through which liquid passes from the casing to the discharge outlet 3.

The liquid consequently follows the course indicated by the arrows in FIGURE 1, the liquid entering the pocket 12 in the upper end of the pump casing through the suction inlet 2,, through the ports 11 in the cover, the liquid then passing downwardly within the inverted L- shaped passage 17 in the cover with which the ports 11 communicate at its upper end. The liquid then flows through the rectangular port 18 into a rectangular recess 19 and thence through the ports 8 in the port plate into the displacement chambers.

Under the reciprocating action of the shoes the liquid is returned into the cover through the ports 8a when the latter are uncovered, the liquid entering a recess 20 and thence through port 21 into an L-shaped passage 22 in the cover and thence through port 15 into the bottom of the pump casing.

After circulating in the bottom of the pump casing the liquid again enters the cover through the port 16 and passes upwardly through the passage 23 and out through the port 13, the liquid then entering the pocket 14 in the upper part of the pump casing and flowing out of the liquid discharge outlet 3.

Ports 15 and 16 being situated in spaced relationship tend to produce a vortex in the liquid which materially assists in the scavenging action of the liquid during its passage through thepump casing.

FIGURES 3, 4, 5, 6 and 7 show clearly the shape and dispostion of the various passages in the cover 9.

Referring now to FIGURES 8 to 12 which illustrate in detail the alternative type of cover shown fitted to the pump casing in FIGURE 2 similar reference numerals are used to indicate similar parts of the two covers.

In this case the liquid no longer circulates through the bottom of the pump casing, the liquid entering the pump casing through the suction inlet 2 passing through the pocket 12, through the ports 11, through the ports 8 into the displacement chambers,-through the ports 8a into the cover as hitherto, the liquid thereafter instead of flowing downwardly through the passage 22 as in the first cover described being deflected laterally and then upwardly through the port 13 and out of the discharge outlet 3 via the pocket 14.

The difference between the passages in the two covers will clearly be apparent from a comparison of FIGURES 4 and 9.

It will be seen that in the case of the cover shown in FIGURE 9 the passage 23 which extended throughout the fulldepth of the coverin FIGURE 4 is foreshortened and i is indicated by reference numeral 23a. Port 2 and pocket 20 communicate direct with the passage 2311, the liquid being deflected upwardly by the lower end of the passage and compelled to pass through the port 13 instead of passing downwardly into passage22 and through port 15 into the pump: casing. Ports 15 and 16 are still uncovered but are not included in the liquid circulatory system and consequently there is no flow of liquid into or out of the lower part of the pump casing, the liquid passing directly to the pump discharge outlet through the passage 23a and pocket 14.

It will be appreciated that an identical pump casing and internal parts will be used foreach type of pump, it being merely necessary to fit the appropriate type of cover.

Furthermore the alternative type of cover can be substituted at any time and without disturbing the pump suction inlet and discharge outlet connections.

I claim:

1. A rotary pump comprising,

(a) a casing having spaced suction inlet and discharge outlet openings in the upper part thereof, and a fiat front face,

(b) said flat front face having inlet "anddischarge ports in its upper part in communication with said inlet and discharge openings by means of internally positioned pockets in the upper part of said casing,

(c) at least one variable volume displacement chamber in said casing and means to vary the volume of said chamber to pump fluid through said casing, (d) laterally spaced inlet and outlet ports in the lower part of the flat front face of said casing which when uncovered communicate with the lower end of said casing permitting circulation of the pumped fluid. through said lower part of the casing,

(e) an inlet and outlet opening for said displacement chamber, said inlet openings being in communication respectively with said inlet and discharge ports in said front face, and v (f) a cover secured to the flat front face of the casing,

said cover including a passage connecting the inlet 1 port in the front face to said inlet opening for the displacement chamber, a second passage connecting the outlet opening of the displacement chamber with the inlet port in the lower part of said front face, and a third passage connecting the outlet port in the lower part of the flat face with the discharge port in the upper part of said front face to insure circulation of liquid through the lower part of the pump casing;

References Cited UNITED STATES PATENTS 2,561,810 7/1951 McCombie 1O3163 2,814,256 11/1957 McCombie 103-163 2,990,110 6/1961 McCombie 230-179 'DONLEY J. STOCKING, Primary Examiner.

WILLIAM L. FREEH, Examiner, 

